This is an application for a Specialized Center of Research in Neonatal Respirtory Distress Syndromes. It proposes an interdisciplinary approach to research on: 1) the causes, prediction, prevention, diagnosis, early and late treatment, and long-term followup of respiratory distress syndromes of the newborn, especially hyaline membrane disease; 2) the development of the lung in the fetus and newborn, with special reference to the surfactant system, to factors determining fluid distribution in the lungs, and to hormonal mechanisms in lung maturation.